Frame with 126mm Rear Wheel - SIS Possible?

[Derek Mark Eddi]

Hi Folks,

I'm trying to upgrade my early nineties Basso Gap road bike, which has a 126mm rear wheel spacing.

I have a Dura Ace drivetrain on this bike, and Dura Ace SIS-capable bar end shifters.

Unfortunately, the back wheel has a SBI hub with a Regina 7-speed freewheel, and it's incompatible
with Shimano SIS. I can use it with the friction setting on the shifter, but the shifting is lousy.
The chain easily rides on top of the freewheel gears unless you tweak the shifter sightly one way or
the other. It's also difficult to downshift on a significant grade.

I'd rather not scrap this bike and replace it because it's in very good shape, and fits well. I'm
considering two options:

1. Finding a replacement freewheel that is SIS compatible.
2. Frame bending to fit a more up to date wheelset with a SIS-compatible freehub.

For #1, I looked on Harris Cyclery's pages and can only find SIS compatible freewheels that go up to
28 teeth or larger. The chain wrap on the Dura Ace RD limits it to 27 teeth max. I haven't seen
something smaller so far that is SIS compatible. If there was, I'd be set!

For #2, this is of course more $$$. The wheels I have are very good and I'd rather not replace them.
I'm not too worried about frame alignment issues if I spread the stays though. The Gap frame has
rear wheel position adjusters if it turns out to be slightly off.

Does anyone remember a better solution for this problem?

Thanks for any help.

-dreq

 

[Dave Mayer]

Mark: I was faced with the same upgrade on a couple of bikes in the last year. I agree that the
shifting on the Regina freewheels is not great with the Shimano SIS shifters.

My recommendation: simply replace your freewheel with a Shimano 7-speed unit from the last 15 years
or so. The freewheels with Uniglide cogs shift reasonable well. You should be able to find a whole
bunch of freewheel options from either Ebay, or the marketplace Usenet forum, or from the backrooms
of more established bike shops. The shops don't often know what inventory they have until they dig a
little. For example: I wandered into my local shop and asked about some retro parts. They were able
to cough up 10(!) new Dura-Ace freewheels in boxes. The Dura-Ace freewheels are highly customizable,
in that if you have the cogs, you can start at a 12-tooth
min., and go up to a 32 max., and anything in between. They are also very well made, unlike 99%
other freewheels I have taken apart, or worn out, and they are serviceable.

The best option is to get a 7-speed Shimano freewheel with Hyperglide cogs. The 7-speed (14-28)
Shimano HG37 unit shifts as well as any current cassette cogset. But as you say, you have no
options: you are limited to 14 for the little cog, and 28 for the biggest. Mechanically, this unit
is inexpensively made, and its body is about 3mm wider than a comparable Dura-Ace freewheel, which
can cause problems on many frames.

I have constructed freewheels with the Dura-Ace bodies and the transplanted Hyperglide cogs, which
allows a 12-28 or 13-28 unit. You may want to check if your derailleur can in fact handle a 28-tooth
cog. You can usually cheat on the recommended derailleur ratings by at least 1 tooth with no
negative effects.

"Derek Mark Edding" <[email protected]> wrote in message
news:[email protected]...
> Hi Folks,
>
> I'm trying to upgrade my early nineties Basso Gap road bike, which has a 126mm rear wheel spacing.
>
> I have a Dura Ace drivetrain on this bike, and Dura Ace SIS-capable bar end shifters.
>
> Unfortunately, the back wheel has a SBI hub with a Regina 7-speed freewheel, and it's incompatible
> with Shimano SIS. I can use it with the friction setting on the shifter, but the shifting is
> lousy. The chain easily rides on top of the freewheel gears unless you tweak the shifter sightly
> one way or the other. It's also difficult to downshift on a significant grade.
>
> I'd rather not scrap this bike and replace it because it's in very good shape, and fits well. I'm
> considering two options:
>
> 1. Finding a replacement freewheel that is SIS compatible.
> 2. Frame bending to fit a more up to date wheelset with a SIS-compatible freehub.
>
> For #1, I looked on Harris Cyclery's pages and can only find SIS compatible freewheels that go up
> to 28 teeth or larger. The chain wrap on the Dura Ace RD limits it to 27 teeth max. I haven't seen
> something smaller so far that is SIS compatible. If there was, I'd be set!
>
>
> For #2, this is of course more $$$. The wheels I have are very good and I'd rather not replace
> them. I'm not too worried about frame alignment issues if I spread the stays though. The Gap frame
> has rear wheel position adjusters if it turns out to be slightly off.
>
> Does anyone remember a better solution for this problem?
>
> Thanks for any help.
>
>
> -dreq

 

[Sheldon Brown]

Derek Mark Edding wrote:

> I'm trying to upgrade my early nineties Basso Gap road bike, which has a 126mm rear wheel spacing.
>
> I have a Dura Ace drivetrain on this bike, and Dura Ace SIS-capable bar end shifters.
>
> Unfortunately, the back wheel has a SBI hub with a Regina 7-speed freewheel, and it's incompatible
> with Shimano SIS. I can use it with the friction setting on the shifter, but the shifting is
> lousy. The chain easily rides on top of the freewheel gears unless you tweak the shifter sightly
> one way or the other. It's also difficult to downshift on a significant grade.
>
> I'd rather not scrap this bike and replace it because it's in very good shape, and fits well. I'm
> considering two options:
>
> 1. Finding a replacement freewheel that is SIS compatible.
> 2. Frame bending to fit a more up to date wheelset with a SIS-compatible freehub.
>
> For #1, I looked on Harris Cyclery's pages and can only find SIS compatible freewheels that go up
> to 28 teeth or larger. The chain wrap on the Dura Ace RD limits it to 27 teeth max. I haven't seen
> something smaller so far that is SIS compatible. If there was, I'd be set!

Dura-Ace will easily handle 28 teeth in back unless you have a HUGE range in front. My Hetchins is
running a 9-speed 12-28 cassette with a short-cage Dura-Ace rear mech. It's on the edge, but that's
cause I've got a big difference in front: 50-28. With a more normal front setup, they'll generally
handle up to 30 in back without problems.

See: http://sheldonbrown.com/gloss_ca-m.html#capacity

> For #2, this is of course more $$$. The wheels I have are very good and I'd rather not replace
> them. I'm not too worried about frame alignment issues if I spread the stays though. The Gap frame
> has rear wheel position adjusters if it turns out to be slightly off.
>
> Does anyone remember a better solution for this problem?

Nope. #1 is the cheapest, #2 is the best, but due to the fact that pre-1997 (pre 9-speed)
Dura-Ace is an orphaned group, you'll indeed be looking at some serious money to upgrade to
anything more than 7.

See: http://sheldonbrown.com/dura-ace.html for more on this.

Sheldon "Upgrades" Brown +------------------------------------------+
| Some are born with a silver spoon, | And some are born without a clue; | Some are born to take
| the biscuit, | Some are born to just make do. |
| |
| When those fatcats drop the big one, | They will turn a penny, too: | They will rent out nuclear
| shelters, | We'll get one with an outside loo! | --The Oysterband | (The greatest band since the
| Beatles) |
+------------------------------------------+ Harris Cyclery, West Newton, Massachusetts Phone
617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

 

[Jon Isaacs]

>Nope. #1 is the cheapest, #2 is the best, but due to the fact that pre-1997 (pre 9-speed)
>Dura-Ace is an orphaned group, you'll indeed be looking at some serious money to upgrade to
>anything more than 7.

Just buy a set of 9 speed Shimano shifters, and with the DA rear derailleur you will shift both 7
and 8 speed cassettes and shimano freewheels just fine.

Jon Isaacs

 

[Qui Si Parla Ca]

derek-<< I'm trying to upgrade my early nineties Basso Gap road bike, which has a 126mm rear
wheel spacing.

<< 1. Finding a replacement freewheel that is SIS compatible.

Sram and DuraAce 7s freewheels are 8s SIS compatible.

<< 2. Frame bending to fit a more up to date wheelset with a SIS-compatible freehub.

This is not hard for a competent bike shop-

<< For #1, I looked on Harris Cyclery's pages and can only find SIS compatible freewheels that go up
to 28 teeth or larger.

We have 7s freewheels in 13-23 and 13-26..DuraAce-

<< Does anyone remember a better solution for this problem?

get a freewheel??

Peter Chisholm Vecchio's Bicicletteria 1833 Pearl St. Boulder, CO, 80302
(303)440-3535 http://www.vecchios.com "Ruote convenzionali costruite eccezionalmente bene"

 

[Grenouil]

"Dave Mayer" <[email protected]> wrote in message
news:[email protected]...
> Mark: I was faced with the same upgrade on a couple of
bikes in the last
> year. I agree that the shifting on the Regina freewheels
is not great with
> the Shimano SIS shifters.
>
> My recommendation: simply replace your freewheel with a
Shimano 7-speed unit
> from the last 15 years or so. The freewheels with
Uniglide cogs shift
> reasonable well. You should be able to find a whole bunch
of freewheel
> options from either Ebay, or the marketplace Usenet forum,
or from the
> backrooms of more established bike shops. The shops don't
often know what
> inventory they have until they dig a little. For example:
I wandered into
> my local shop and asked about some retro parts. They were
able to cough up
> 10(!) new Dura-Ace freewheels in boxes. The Dura-Ace
freewheels are highly
> customizable, in that if you have the cogs, you can start
at a 12-tooth
> min., and go up to a 32 max., and anything in between.
They are also very
> well made, unlike 99% other freewheels I have taken apart,
or worn out, and
> they are serviceable.
>
> The best option is to get a 7-speed Shimano freewheel with
Hyperglide cogs.
> The 7-speed (14-28) Shimano HG37 unit shifts as well as
any current cassette
> cogset. But as you say, you have no options: you are
limited to 14 for the
> little cog, and 28 for the biggest. Mechanically, this
unit is
> inexpensively made, and its body is about 3mm wider than a
comparable
> Dura-Ace freewheel, which can cause problems on many
frames.
>
> I have constructed freewheels with the Dura-Ace bodies and
the transplanted
> Hyperglide cogs, which allows a 12-28 or 13-28 unit. You
may want to check
> if your derailleur can in fact handle a 28-tooth cog. You
can usually cheat
> on the recommended derailleur ratings by at least 1 tooth
with no negative
> effects.
>
>
> "Derek Mark Edding" <[email protected]> wrote in message
> news:[email protected]...
> > Hi Folks,
> >
> > I'm trying to upgrade my early nineties Basso Gap road
bike, which has a
> > 126mm rear wheel spacing.
> >
> > I have a Dura Ace drivetrain on this bike, and Dura Ace
SIS-capable bar
> > end shifters.
> >
> > Unfortunately, the back wheel has a SBI hub with a
Regina 7-speed
> > freewheel, and it's incompatible with Shimano SIS. I
can use it with
> > the friction setting on the shifter, but the shifting is
lousy. The
> > chain easily rides on top of the freewheel gears unless
you tweak the
> > shifter sightly one way or the other. It's also
difficult to downshift
> > on a significant grade.
> >
> > I'd rather not scrap this bike and replace it because
it's in very good
> > shape, and fits well. I'm considering two options:
> >
> > 1. Finding a replacement freewheel that is SIS
compatible.
> > 2. Frame bending to fit a more up to date wheelset with
a SIS-compatible
> > freehub.
> >
> > For #1, I looked on Harris Cyclery's pages and can only
find SIS
> > compatible freewheels that go up to 28 teeth or larger.
The chain wrap
> > on the Dura Ace RD limits it to 27 teeth max. I haven't
seen something
> > smaller so far that is SIS compatible. If there was,
I'd be set!
> >
> >
> > For #2, this is of course more $$$. The wheels I have
are very good and
> > I'd rather not replace them. I'm not too worried about
frame alignment
> > issues if I spread the stays though. The Gap frame has
rear wheel
> > position adjusters if it turns out to be slightly off.
> >
> > Does anyone remember a better solution for this problem?
> >
> > Thanks for any help.
> >
> >
> > -dreq
> >
>
FWIW I agree with Dave - you can customize a D/A seven speed FW body with hyperglide sprockets with
a bit of work with a file to make them fit. Or you can buy a cheap Shimano HG37 seven speed 14-28
freewheel and customize that by replacing sprockets. You can use a mix of hyperglide and uniglide
sprockets, or SunRace sprockets - which seem to be a hyperglide copy - with some filing. I even
built an eight speed freewheel on an HG37 body by replacing the lockring with a 13T screw on DuraAce
sprocket - won't fit a 126mm spacing though.

Up to at least 28T doesn't seem to be a problem with Shimano road rear dérailleurs.

 

[A Muzi]

"Derek Mark Edding" <[email protected]> wrote in message
news:[email protected]...
> Hi Folks,
>
> I'm trying to upgrade my early nineties Basso Gap road bike, which has a 126mm rear wheel spacing.
>
> I have a Dura Ace drivetrain on this bike, and Dura Ace SIS-capable bar end shifters.
>
> Unfortunately, the back wheel has a SBI hub with a Regina 7-speed freewheel, and it's incompatible
> with Shimano SIS. I can use it with the friction setting on the shifter, but the shifting is
> lousy. The chain easily rides on top of the freewheel gears unless you tweak the shifter sightly
> one way or the other. It's also difficult to downshift on a significant grade.
>
> I'd rather not scrap this bike and replace it because it's in very good shape, and fits well. I'm
> considering two options:
>
> 1. Finding a replacement freewheel that is SIS compatible.
> 2. Frame bending to fit a more up to date wheelset with a SIS-compatible freehub.
>
> For #1, I looked on Harris Cyclery's pages and can only find SIS compatible freewheels that go up
> to 28 teeth or larger. The chain wrap on the Dura Ace RD limits it to 27 teeth max. I haven't seen
> something smaller so far that is SIS compatible. If there was, I'd be set!
>
>
> For #2, this is of course more $$$. The wheels I have are very good and I'd rather not replace
> them. I'm not too worried about frame alignment issues if I spread the stays though. The Gap frame
> has rear wheel position adjusters if it turns out to be slightly off.
>
> Does anyone remember a better solution for this problem?

There are seven speed SIS compatible frewheels available in smaller sizes.

If you so desire, it's straightforward to realign to 130mm and convert to modern nine or ten
gearing. Even a nice bike like a Gap is frequently not _perfectly_ straight so an aligment to a
spoke thickness wider per side is trivial, often within the range of error you 're riding now.
--
Andrew Muzi http://www.yellowjersey.org Open every day since 1 April 1971

 

[Alex Rodriguez]

In article <[email protected]>, [email protected] says...
>Hi Folks, I'm trying to upgrade my early nineties Basso Gap road bike, which has a 126mm rear wheel
>spacing. I have a Dura Ace drivetrain on this bike, and Dura Ace SIS-capable bar end shifters.
>Unfortunately, the back wheel has a SBI hub with a Regina 7-speed freewheel, and it's incompatible
>with Shimano SIS. I can use it with the friction setting on the shifter, but the shifting is lousy.
>The chain easily rides on top of the freewheel gears unless you tweak the shifter sightly one way
>or the other. It's also difficult to downshift on a significant grade.
>
>I'd rather not scrap this bike and replace it because it's in very good shape, and fits well. I'm
>considering two options:
>
>1. Finding a replacement freewheel that is SIS compatible.

A dura-ace freewheel will work. You will see used, and sometimes new, ones on
rec.bicycles.marketplace every so often.

>2. Frame bending to fit a more up to date wheelset with a SIS-compatible freehub.

If you get an DA 8spd freehub you don't need to spread your frame. The hub's end nuts have tapered
ends so that they spread the frame for you as you insert the wheel.

-----------------
Alex __O _-\<,_ (_)/ (_)

 

[Derek Mark Eddi]

Hi Folks,

My first attempt - after trying four local shops, I found a Sun 13-28 freewheel at Performance in
Chapel Hill that looked promising, and spun it on.

The Dura Ace derailleur handles the 28 tooth gear. There was enough B-tension adjustment to keep the
top pulley from rubbing.

The only downside is that the SIS shifting isn't perfect. It takes two clicks instead of one to get
the chain onto the 28T sprocket. None of the other shifts seem misaligned, so I may just live with
it for a while.

Thanks for all the great advice!

-dreq